Experimentally verified procedure for determining dynamical model of the ETM MEMS structures

Electro Thermo Mechanical (ETM) actuators play important role in rapidly growing MEMS area, particularly as a part of the more complex MEMS assemblies. Compared to the other types of micro actuators, ETM actuators generate large force with the price of the high power consumption. Tradeoff between these two properties, and design requirements arise necessity for the development of its accurate dynamical mathematical model. The accurate model leads towards the optimal design and, if necessary, can be used for a subsequent design of control algorithms. In general, the mathematical model consists of the three sub-models-electrical, thermal and mechanical and is should be considered as multi-physics phenomena with thermal one playing a dominant role. The dynamics of particular sub-model is determined by combining of the theoretical and Finite Element Analysis approach, verified with the available experimental data. Simultaneous application of these three approaches requires a definition of a procedure that leads toward determination of the model. In this paper, mentioned procedure is described in details, and is subsequently illustrated on the example of two hot arm bimorph thermal actuator fabricated using Poly-Multi User MEMS Process (PolyMUMPs).